This is the honest version of the story, and at the same time the strongest argument for a partner who really knows the platform.
Creatio is a platform choice. That means that at the start you answer architecture questions that a standard package has already answered for you: which process model you use where, how you structure your data model, what becomes no-code and what calls for pro-code, which parts of Creatio you use and which you leave out, how you integrate with your existing systems and which system leads for which data.
Answering those questions well at the start saves months of work later. Answering them wrongly, or not answering them at all, is the most common cause of Creatio implementations that get stuck.
We ask those questions explicitly, work out the answers in an architecture design, and only start building once that design has support. That costs more up front and always pays for itself.